Henry d



H. D. DEANE. Perforated Propeller Blade.

No. 241,124. Patented May 10, 1881.

N. PETERS. Fholo'Lithographor, Wilhlngtnn, D. C.

UNITED STATES PATENT OFFICE.

HENRY D.

DEANE, OF BROOKLYN, NEW YORK.

PERFORATED PROPELLER-BLADE.

SPECIFICATION forming part of Letters Patent No. 241,124, dated May 10,1881. Application filed August 17, 1877. Patented in England March 29,1878.

To all whom it may concern:

Be it known that I, HENRY DANIEL DEANE, a resident of the city ofBrooklyn, Kin gs county, and State of New York, have invented certainnew and useful Improvements in Screw-Propellers, of which the followingis a specification.

This invention relates to that class of devices for propelling vesselsknown as screw-propellers and in the present instance it consists in anovel application to the various blades of such propellers of a seriesof perforations, the nature, use, and practical operation of which willbe hereinafter fully set forth and described.

In the drawings, which form an essential part of this specification,Figure 1 is a view in perspective of a screw-propeller in which is fullyembodied my invention, and Fig. 2 is a vertical section of a singleblade of such a propeller.

The same reference-letters found in the two drawings will locate andpointout corresponding parts.

My invention consists in forming in the body of the various blades of ascrew-propeller a series of perforations, which maybe of such size andform, and located therein at such points, as

practice may show to be the most effectual for the purpose.

A B O D represent the blades of a screwpropeller, which are cast in theusual form.

a. designates the series of perforations formed therein when the bladesare cast, or by drillin g thereafter. forations is conical, in the formof a truncated cone, or that of a tunnel or funnel shape, as plainlyshown in the drawings; but their shape may be modified withoutmaterially changing the character of my invention.

It will be seen that as the propeller revolves the wide mouth of theperforations in each blade is presented to the water, a portion ofwhich, as it impinges on the blade and perforations, is,by the peculiarshape of the walls of the perforations, ejected therefrom to the rear ofthe blades with considerable force, while the blade itself, by theincrease of the superficial area of its surface, obtains a greater holdupon the body of water upon which it is acting.

The invention aims to accomplish the following objects: the provision ofincrease the speed a screw-propeller that shall of the vessel and Theform I prefer for these perdecrease the consumption of fuel; and myinvention secures the following advantages in securing those desiredends: an increase of the superficies of the propellingsur ace withoutenlarging the size of the blades. This will be readily understood asbeing due to the amount of surface gained by reason of the walls of theconical perforations, the direct action thereon by the water naturallyincreasing the propelling power or action of the blade as it impinges onthe water. As the blades revolve, the water that is rapidly ejectedthrough the base of the conical perforations in each blade formspowerful jets or columns of water, which are met by each sueceedin gblade. In fine,this action of the perforations on the water is simplyforming what, in the use of the ordinary propeller, would be backwaterinto a strong current, which is always moving in the reverse way towardand impinging on the various blades of the propeller, thus giving themthe increased resistance sought for.

In the use of the common propeller it is a well-settled fact that avacuum forms behind each of the blades, resulting in decreasing thepropelling-power. By the use of my perforated blades all objections ofthis character are obviated, it being impossible for a vacuum to form.It will also be found that these perforated blades will act as aregulator or governor to the engines, which are quickly checked byreason oftheresistance offered to theblades, and this resistancenaturally increases with any increase of the number of revolutions ofthe propeller; this inasmuch as the friction against the surface of thewalls of the various conical perforations becomes more intense and thecurrents of water ejected from the base of the perforations run withgreaterforce against the rapidly-revolving blades. The resistance thusmet therefore serves to regulate and control the speed of the engines,which are thus caused to work easily and steadily, preventingunnecessary wear, strain, or breakage, either on wheels or engine.

It is a well-known fact that in the present use of screw-propellers eachblade thereof is deprivingits succeeding blade of its gripe upon thewater, the blades working, as it were, in foam instead of solid water,this, of course, resulting in a great loss of power. Therefore theeradication of this difliculty was a desideratum long wished for, and itis fully and completely accomplished by the use of my perforated blades.Furthermore, a very considerable saving of fuel will be eifected by theuse of the perforated blades, not only by increasing the speed andshortening the voyages of steamers, but by economizing the dailyconsumption of fuel while so doing. It may be here argued, however, thatunless the number of revolutions made by the engines be diminished therecannot be a saving of fuel, for the reason that a certain amount of coalmust be consumed for every stroke of the pistons. To increase the speedof the engines, therefore, would neither save fuel nor increase thespeed of the vessel. The difficulty lies in lessening the speed of theengines and increasing that of the vessel, such being the only waywhereby any permanent advantage can be gained in speed and in economy offuel. ally true in the use of the solid blades of an ordinary propeller;but the reverse is the case in the use of myimproved blades havingconical perforations. For it an enormous weight of backwater be takenout of any wheel the engines are at once free, and can work quicker orbe operated with a less pressure of steam, can save fuel, and at thesame time be doing the same propelling duty; but if by the simple meansof conical perforations in the blades the This is liter- I ordinarybackwater be converted into a torrent pouring against the successiveblades as they revolve, more steam can be used with advantage, and anincrease of speed must necessarily result.

It will be plainly obvious to those skilled in steam navigation that"essels provided with the perforated blades can be much more easilyhandled when towing or running in a seaway, and if disabled or runningunder canvas only, the blades of the propeller will offer less resistance, as the water will pass freely throu gh the perforations. Inreversing the movement the small openings at the rear of the bladespresented to the water have no effect thereon, and the propeller willoperate as well as in ordinary cases.

Having thus fully described my invention, what I claim as new is Ascrew-propeller the several blades ofwh ieh are provided with a seriesof perforations, such perforations being in the form ofa cone, atruncated cone, or tunnel or funnel shaped, such perforatedpropeller-blmles applied and operating as and for the purposessubstantially as herein shown and set forth.

HENRY D. DEANE.

Witnesses:

A. L. MUNsoN, E; G. YVARD.

